The most commonly used illuminating device worn on a hard hat by miners, construction workers, or others employs a single incandescent bulb which is connected by a power cable to a battery pack adapted to be clipped to the belt of the wearer. Usually the battery is a 3.6 or four volt battery. The incandescent bulb is hermetically sealed within a housing to prevent methane gas from being ignited by the hot incandescent filament. The front lens is usually of glass and if it breaks, the incandescent bulb is spring biased to shift forward and open its energizing circuit to prevent ignition of methane gas. One problem with such incandescent bulbs is that they project only spot beam, usually of about 40 to 50 lumens, and hence do not provide much peripheral or side lighting.
Another form of illuminating device worn on a hard hat is disclosed in U.S. Pat. Nos. 3,953,725 and 4,002,895, which disclose a fluorescent bulb in a sealed housing attached to a hard hat. While the fluorescent lamp was able to provide increased lumens and better peripheral lighting, the device was large and included a large, oblong housing which struck, laterally outward from the sides of the hard hat and could be caught on or hit against obstructions while the wearer was working.
The safety codes of various occupations are quite stringent as to the requirements of the illuminating device. It must operate off a low voltage power source and for an extended period of time before being recharged. For instance, a typical miner's illuminating device should operate 10 hours before having to be recharged, should operate from a 4 volt battery. Further, the luminating device must be lightweight so that the wearer does not have an uncomfortable weight on his head. Further, as above explained, the preferred illuminating device should fit within a small volume, for example, less than about 31/2" on each side.
Accordingly, an object of the present invention is to provide a new and improved illuminating device for wearing on a cap.
Another object of the invention is to provide an illuminating device for a cap which selectively provides for either a spot beam or for a wider beam with more peripheral lighting.
A still further objective of the invention is to provide a cap lighting device having both an incandescent and fluorescent light bulb within the same housing.